28728617637 has 4 divisors (see below), whose sum is σ = 38304823520. Its totient is φ = 19152411756.

The previous prime is 28728617629. The next prime is 28728617647. The reversal of 28728617637 is 73671682782.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28728617637 - 2³ = 28728617629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28728617647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4788102937 + ... + 4788102942.

It is an arithmetic number, because the mean of its divisors is an integer number (9576205880).

Almost surely, 2^28728617637 is an apocalyptic number.

It is an amenable number.

28728617637 is a deficient number, since it is larger than the sum of its proper divisors (9576205883).

28728617637 is an equidigital number, since it uses as much as digits as its factorization.

28728617637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9576205882.

The product of its digits is 9483264, while the sum is 57.

The spelling of 28728617637 in words is "twenty-eight billion, seven hundred twenty-eight million, six hundred seventeen thousand, six hundred thirty-seven".